Method of curing tobacco



A. C. BUENSOD. METHOD OF CURING TOBACCO. APPLICATION FILED OCT. 26. 191.5.

Patented May 4, 1920.

2 SHEETSSHEET lfan/ran ,fiy

A TTORNEY WITNESSES.

A. C. BUENSOD.

METHOD OF CURING TOBACCO. APPLICATION FILED OCT. 26. 1 915..

1 ,33 9 ,374, Patented May 4, 1920.

2 SHEETSSHEET 2- WITIVESSESI -ALFBED CHARLES'TBUENSOD, or NEW TREATING 00. 1110;, or NEW YORK, n.1, A

YORK. N. Y., ASSIGNOB TO .THE TOBACCO CORPORATION OF NEW YORK.

METHOD OF CURING TOBACCO.

T 0 all whom, it may concern:

Be it known that I, ALFRED CHARLEs BUENsoD, a citizen of the United States of America, residing in the city of New York, county of New York, and State of New York, have invented certain new and useful Improvements in Methods of Curing Tobacco, of which the following is a full, clear, and exact description.

The method herein described is related particularly to the curing of green tobacco leaves. Wherever in the following description the word tobacco is used, it will be understood that it refers particularly'to such green tobacco leaves. i

It is well known to those skilled in the art that the present method of treating tobacco is to place the same within small, tightly closed barns, after which the barn is made air tight. Fire places are provided along near the floor line of the barn and metal flues extend through the barn and connect with the fire places, whereby the heat is conducted inside of the barn for heating the-tobacco. When the tobacco is placed Within the barn, hung beneath the tobacco, and the temperature within the barn is regulated by the amount-of fuel burned in the fire places. in some of these barns a ventilator is provided at the top and with small openings made in the wall near the floor line. This ventilator and these openings may be, opened or closed as desired so as to make it possible to create a draft through the tobacco contained in the barn. The above described arrangement of heating and ventilating requires constant attention on the part of the operator, and in many cases, he is unable to properly control these conditions. Moreover, when such a method of treatment is used, it is impossible to regulate the percentage of moisture or the eva orative tempera- .ture within the barn.

,drying of T e percentage of moisture in the tobacco throughout the treatment, governs the steps I every point, and the sensible temperature and evaporative temperature maintained during treatment determines the rate of the tobacco and the percentage of moisture in the tobacco. It will be seen,

' therefore, that the present process cannot be carried out with any degree of certainty without an evaporative temperature, aswell as a sensible temperature control. The (proc- Specification 01: Letters Patent.

, ture of the air within the same.

a thermometer 1s.

.7 as is possible.

' certainty,

of the process at f judge the amount of heat necessar My process also provides means,

ess, as now practised, is entirely'dependent upon the outside weather conditions as the sensible temperature maintained inside the barn determines the evaporative tempera- Ittherefore follows that no definite rule of raising i the sensible temperature and maintaining the same at a predetermined point can be followed in the present practice and at the same time maintain the proper moisture conditions.

In my invention, I have sought to obviate the above mentioned disadvantages by providing a process in which the sensible temperature, the evaporative temperature and consequently the rate of drying are under absolute control at all times, independent of outside weather conditions or the judgment or attention of the operator. Furthermore, by means of my process, different batches of tobacco will all have the same treatment, thus making the finished product as uniform as possible. By reason of the proper air control provided by my process, the tobacco is supplied with air so conditioned as to allow the physical and chemical changes to take place in the tobacco and to so control them that the qualities of the tobacco are always as near ideal This positive control makes it possible to meet the required conditions of any type of tobacco or any changes in the composition of the leaf due to different rowing conditions. It also makes possible the attainment of the desired color by maintaining a delicate control of the conditions at a predetermined point.

Moreover, by controlling the condition of the air, my invention provides a process which materially shortens the length of time of drying the tobacco over present practice andat the same time provides with a uniform finished product. My process also obviates the services of a skilled curer, who, in present practice, must constantly watch the tobacco day and night, to to carry out the process successfully. also avoids all danger of damage to the tobacco through any negligence or carelessness on the part of the curer.

Furthermore, I have sought to provide a process in which the air used in curing the tobacco may be used over and over again. whereby Patented May 4, 1920. Application filed October 26, 1915. Serial No. 58,045. i

y process when the moisture content of the air is above apredetermined point, the air may be automatically replenished with outside air or the superfluous moisture may be taken out of the air by suitable condensing means.

My process may be carried out by any suitable means and preferably consists in general, of a system of automatic control in its most simple form, consisting preferably of sensible temperature and evaporative temperature regulating devices. These devices comprise preferably thermostats, two

in number. One of these is controlled by sensible temperature and is hereinafter referred to as the dry thermostat, and the other controlled by the evaporative temperature, and hereinafter referred to as the wet thermostat. The wet thermostat is of the same construction as the dry thermostat except that its expansive members are covered with a film of water maintained by a wick dipped in water or by a spray or any other suitable means. The condition of the air within the treating chamber is measured by means of these instruments and they are placed in any suitable position. The amount of heat which is introduced into the treating chamber is governed and controlled by the dry thermostat. which operates on the means for controlling the sensible temperature. The evaporative temperature within the treating chamber is automatically controlled by the wet thermostat: It will thus be seen that by means of the dry thermostat and wet thermostat any desired sensible temperature and evaporative temperature may be maintained in the treating chamber. Obviously. these temperatures may be varled either manually or automatically In any definite interval of time. The process herein set forth describes only one of the several methods by which the above results can be obtained. In the drawings. forming part of this application. I have shown an apparatus. and a modification thereof for carrying out my process.

It should be noted that one of the specific advantages of the invention herein described resides in the fact that the air'used for curing can'be used over and over again, thus materially reducing the quantity of heat required to maintain the necessary temperature conditions.

In the drawings: Figure 1 shows. in a diagrammatical manner, a form for carrying cut my process wherein the air may be replenished.

Fig. 2 shows in a diagrammatical manner. a modified form wherein condensing means are used.

Referring now to the drawings and more particularly to Fig. 1. 5 represents a treating chamber in which the tobacco leaves 6 are hung after being placed on suitable supports 7. Near the top of the treating chambranch 13 and the duct 12 with a branch 11L.

Arranged in the branch duct 13 is a damper 15. In the branch duct 14 is a damper 16. Arranged in the outer end of the duct 11, just beyond the branch duct 13, is a damper 17. The dampers 16 and 17 are connected together by means of a link 18 and the dampers .17 and 15 are connected together by means of a link 19. By this ar rangement, the dampers 15 and 16 will be opened when the damper 17 is closed. The damper 15 is connected by means of a link 20 to an air motor 21 by which the dampers 15, 16 and 17 are operated, as hereinafter described. 7

Arranged at the inner end of the duct 11 is a dry thermostat 22 and a wet thermostat 23. 24 is an air tank for supplying compressed air to the thermostats. 25 is a supply pipe which carries the compressed air to the dry and wet thermostat by means of pipes 26 and 27, respectively. Pipes 28 and 29 connect the wet thermostat 23 with the air motor 21. I

Arranged at the outer end of the duct 10 is a fan 30 which is driven preferably by a motor 31. This fan draws the air through the ducts 11 and 12 and forces it through the pipe 33 with a suitable heating medium. In

the pipe 33 is arranged a direct acting diaphragm valve 31 and connecting this valve with the dry thermostat 22 is a. pipe whereby the flow of the heating medium to the coil may be controlled by the dry thermostat. 1

Arranged between the fan30 and heating coil 32 is the humidifying means ofthe apparatus. This means preferably comprises spray nozzles '36 which are connected with the supply pipe 37. A direct acting diaphragm valve 38 is provided in the pipe 37 and connecting this valve with the pipe 28 leading from the wet thermostat 23. is a pipe 39. A. manually operated valve 40 is placed in the pipe 37 whereby the water or other humidifying liquid may be shut off duct. In this form of the apparatus, a duct 41 extends outwardly from the opening 9 of the treating chamber and connecting the outer end of thisduct with the outer end of the duct 10 is a vertical duct 42. The duct 41 is provided with an enlarged portion 43 and extending longitudinally through this portion is a partition 44, thus providing passage ways or ducts 46 is provided any suitable condensing means, which, in this case, .is a condensing coil 47. 48 is the supply pipe through which the condensing fluidis carried to the coil. In this pipe is arranged the reverse acting diaphragm valve 49. Connecting this diaphragm valve with the pipe 28 leading from the wet thermostat 23 is a pipe 50. Atthe inner end of the duct 46 is arranged a damper 51 and arranged at the inner end of the duct 45 is a damper 52. These dampers are connected together by means of a link 53, so

that they will operate in unison and so that one will be closed when the other is open. The link 53 is connected by means of the link 54, to the operating arm of the air motor This air motor is connected with the air pipe 50 by means of the pipe 56.

' When using the apparatus shown in Fig. 1, the dampers and 16 are normally closed and the damper 1 7 is normally open. The dry and wet thermostats are set at predetermined temperatures at the beginning of the treating process. The fan forces the air through the chamber and as it passes through the duct 11, it-will affect the dry thermostat so as to permit the heating medium to pass through the coil 32 and heat the air which is forced into and through the heating chamber. The air will continue to a rise in temperature until the predetermined point at which the dry thermostat has been set is reached. A further rise in temperature will cause the dry thermostat to aotuate the diaphragm valve 34 and thus shut off the supply of heating medium to the coil 32. When the temperature of the air coming from the chamber is below the predeter-' mined point, the dry thermostat will again operate to open the diaphragm valve 34 and thus again supply coil 32 with the heating medium. The wet thermostat 23, which is subject to the evaporative temperature in the treating chamber is set at a temperature lower than the dry thermostat'22 at a predetermined difference, which may be varied at will during the treating process. By the useof the wet thermostat, a means is afforded of definitely controlling the rate at which evaporation occurs from the tobacco and also controlling the degree of dryness to which the tobacco can ultimately be reduced.

VVhenthe moisture in the tobacco is below the predetermined point and the valve 40 is open, t e wet thermostat 23 will control the diaphr gm valve 38 so as to cause a suitable and 46. Within the duct.

damper 17 and openthe dampers 15 and 16.

small quantity of fresli air taken in.

humidifying liquid to be sprayed into the duct 10 through the spray nozzles 36. When the percentage of moisture in the air coming from the treating chamber is above the predetermined point, the diaphragm valve '38 will be closed by the air pressure so as to shut oil the supply of fluid from the spray nozzles and the air motor 21 will also be operated so as to partially or wholly close the but a portion or all of it will bepassed out-- wardly through the branch duct 13, and

air from the atmosphere will be taken in through the branch duct 14. By this means, the air in the chamber is automatically completely changed or is replenished accordin to the condition of the air. Under norma conditions, the dampers will only be partially open so that onl a small partof the air will be driven out ro'm the duct 9 and a In the modified form shown in Fig. 2,. when the moisture content of the air is above a predetermined point, the diaphragm valve 49 will be operated so as to allow the condensing medium to pass through the pipe 48 and coil 47. At the same time that this valve is operated, the air motor is also operated, whereby the damper 52 will be closed and the damper 51 will be opened, thus deflecting the air through the duct 46 and over the condensing coil 47 In passing over the coil 47, the superfluous moisture is taken out of the air and when it has been reduced to the predetermined percentage the dampers 51 and 52are again operated to by-pass a whole or part of the air through the duct 45. The dampers 51 and 52 are erated wholly or partially according to tecondition of the air passingthe wet thermostat 23. I If desired, the valve 49 may be dispensed with, thus allowing the cooling medium to pass continuously through the coil 47. The control would then be accomplished by passing the whole or a part of the air through either of the ducts 45 or 46. On the other hand, if desired, the duct 45 and dampers 51 and 52,-together withthe air motor 55 and the connections to these parts may be omitted and the amount of cooling medium passing through the coil controlled by the valve 49.

treated product is always under control.

While have shown and described one, type of apparatus and a modification there- 'of for carrying out my process, it is obvious I that other devices may be usedfo'r carrying out the same with equal efiiciency without departing from the spirit of my invention or the scope of the appended claims, and I do not, therefore, wish to limit myself to the exact apparatus herein shown and described.

Having thus described my invention, what I claim is:

1. A method of curing green tobacco which consists in confining the tobacco in a substantially air-tight chamber, forcing a current of air through the tobacco in the chamber, heating the air before it is forced through the tobacco, then increasing the moisture content of the air by evaporation from the tobacco until the rate of evaporation from the tobacco is very slight, leading the air after it has passed through the tobacco from the chamber andreturning it to the same, and regulating the temperature and relative humidity of the air in the chamber by the condition of the air after it has passed through the tobacco.

2. A method of curing tobacco which consists in confining the tobacco in a substantially air-tight chamber, forcing a current of air through the tobacco in the chamber,

heating the air in the chamber, leading the air after 'it has passed through the tobacco from the chamber and returning it to the 4 same, condensing a part of the moisture the exitafter 'it has from the air after it has passed through the I tobacco, increasing the moisture content of the air by evaporation from the tobacco until the rate of evaporation from the tobacco is very slight, and regulating'the temperature and relative humidity of the air which is used'in curing the tobacco by the condition of the air at the exit after it has passed through the tobacco.

' 3. A method-of curing tobacco which consists in confining the tobacco in a substan-- tially air-tight chamber, forcing acurrent of'air through the tobacco in the chamber, heating the air. in the chamber, leading the air after it has passed through the tobacco from the chamber and returning itto .the same, by-pas sing a part of the air after it has passed through the tobacco, condensing the superfluous moisture from the air so bypassed, and regulating the temperature and relative humidity of the air used for curing the tobacco by the condition of the air at passed through the tobacco.

In testimony whereof I have hereunto signed my name inthe presence of two sub-.

scribin witnesses. i v A FRED CHARLES BUENSOD.

Witnesses: GEO. E. NA E,

JAMES 0. GRANT. 

